***Update: Even though it appeared so, the old dampers are not the factory set …but still old enough.***
I have this set of Bilstein B6 dampers since the late summer when it was on sale. Now that I brought my BMW 1800 to its winter refuge, I really could take advantage of that place. By the way, thanks a lot Karl-Heinz for the shelter and the support.
Even though the pre-owner reassured me that the dampers were fine, all four of them were completely busted. Most probably, they were the factory parts.
Shocks on the rear…
We started on the rear since it’s the easier part of the job. The shocks are mounted collaterally to the springs. We didn’t need any special tools, but I can really recommend having access to a car lift.
The tops of the shocks are mounted directly to the car’s body – into the shock towers obviously. The bottom end is mounted on a threaded stud next to the drive shaft. It’s a good idea to let them soak in oil for a while before ever touching them.
While still with the wheels on the ground, we loosened the double nuts on the rod. They are accessible from the trunk. After lifting the car, we could easily push down the rods since they were broken. After loosening the nuts on lower studs we had to lever off the shocks with a bar, but this sounds way more severe than it actually was.
After cleaning and checking the studs and nuts, it took us a while to get the new ones in. In the end we found that it is the easiest way to mount them loosely in shock towers first and finally get them on the studs with a few careful hits of a plastic hammer. The cleaned nuts were fastened with screwlock. The Bilsteins come with all the required rubber bushings and shims. One goes on the inside and one on the outside. The rod in the shock tower is secured with a locking nut. We used an Allen key to keep the rod from turning while fastening. It takes some delicacy of feeling as the bushing shouldn’t be squeezed too much.
…and struts on the front
After a coffee break, we went on to the real challenge: the front struts. The “Neue Klasse” has so called MacPherson struts on the front axle, which means the dampers are surrounded by the spring coils. The wheels needed to come off first in order to clear enough handling space. We settled the lower wishbones onto jackstands to compress the springs. Now the spring spanners came into play. It took some attempts to find the right position to fasten them. Afterwards the car went back up again.
It took us some oil and even more muscle to unscrew the 27mm nut holding the rod in the strut bearing. It has been there for probably 45 years. The rod went down on its own pretty much. I removed the strut bearing and pulled the whole strut through the hole were the bearing was before. With it came a lot of fluid and a little tag saying “Genuine BMW parts”! Totally busted, but they still might have some historical value though.
I found out that all the sticky stuff around wasn’t dirt or grease for the most part. It was spray coating – 45 years old Swedish spray coating. We decided only to clean off the essential parts and leave the outside with its ‘patina’.
The struts go in pretty much in the reverse order. I really recommend not to do that alone. I slid in the strut through the shock tower and the spring while Karl-Heinz held the whole assembly in position. He put on the new strut bearing and the rod and I lowered the car on the jack stands again. The whole assembly moved into place. After tightening all nuts on the rod and the bearing the jacks could be removed and the wheels were put back on.
The test drive on the next day really revealed that it was a sound decision to replace the dampers. Small ripples in the road just passed smoothly without loosing feedback. Since we got in the wake of an autumn storm the roads were covered with mushy leafs and shattered twigs. We couldn’t go into full test mode, but the crosswind surely got nothing on us. I guess we have to wait for spring for more excessive test driving. Nevertheless we definitely had a satisfying feeling when we rolled back into the winter refuge.